2004 ISUZU TF SERIES battery

SUPPLEMENTAL RESTRAINT SYSTEM 9A-27

Service Precautions for SRS
Component Service
CAUTION: When fasteners are removed, always
reinstall them at the same location from which
they were removed. If a fastener needs to be
replaced, use the correct part number fastener fo
r
that application. If the correct part number
fastener is not available, a fastener of equal size
and strength (or stronger) may be used. fasteners
that are not reused, and those requiring thread
locking compound will be called out. The correct
torque value must be used when installing
fasteners that require it. If the above conditions
are not followed, parts or system damage could
result.
WARNING: WHEN PERFORMING SERVICE ON O
R
AROUND SRS COMPONENTS OR SRS WIRING,
FOLLOW THE PROCEDURES LISTED BELOW TO
TEMPORARILY DISABLE THE SRS. FAILURE TO
FOLLOW PROCEDURES COULD RESULT IN
POSSIBLE AIR BAG DEPLOYMENT, PERSONAL
INJURY OR OTHERWISE UNNEEDED SRS
REPAIRS.
The SRS control unit in Driver–Passenger SRS can
maintain sufficient voltage to cause a deployment for
up to 15 seconds after the ignition switch is turned
“OFF,” the battery is disconnected, or the fuse
powering the SRS control unit is removed.
Many of the service procedures require removal of the
“SRS” fuse, and disconnection of the air bag assembly
from the deployment loop to avoid an accidental
deployment. If the air bag assembly is disconnected
from the deployment loop as noted in the “Disabling
the SRS” procedure that follows, service can begin
immediately without waiting for the 15 second time
period to expire.

Disabling The SRS
Removal
Turn the ignition switch to “OFF” and turn the steering
wheel so that the vehicle's wheels are pointing straight
ahead.
1. Remove SRS fuse “SRS” from left dash side lowe
r
fuse block or disconnect battery.
2. Disconnect yellow connector at the base o
f
steering column.
3. Remove glove box assembly; Refer to “Passenge
r
air bag assembly replacement” in this section.
4. Disconnect passenger air bag assembly yello
w
connector behind the glove box assembly.
CAUTION: With the “SRS” fuse removed and
ignition switch “ON,” the “AIR BAG” warning lamp
will be “ON.” This is normal operation and does
not indicate an SRS malfunction.
Enabling The SRS
Installation
Turn ignition switch to “LOCK” and remove key.
1. Connect yellow connector passenger air bag
assembly.
2. Install glove box assembly. Refer to “Passenge
r
Air Bag Assembly Replacement” in this section.
3. Connect yellow connector at the base of the
steering column.
4. Install “AIR BAG” fuse “SRS” to left dash side
lower fuse block or connect battery.
Turn ignition switch to “ON” and verify that the “AIR
BAG” warning lamp flashes seven times and then
turns “OFF.” If it does not operate as described,
perform the “SRS Diagnostic System Check” in this
section.

Handling / Installation / Diagnosis
1. Air bag assembly should not be subjected to
temperatures above 65

C (150

F).
2. Air bag assembly, and SRS control unit should not
be used if they have been dropped from a height
of 100 centimeters (3.28 feet) or more.
3. When a SRS control unit is replaced, it must be
oriented with the arrow on the SRS control unit
pointing toward the front of the vehicle. It is ver
y
important for the SRS control unit to be located flat
on the mounting surface, parallel to the vehicle
datum line. It is important that the SRS control unit
mounting surface is free of any dirt or other foreign
material.
4. Do not apply power to the SRS unless all
components are connected or a diagnostic chart
requests it, as this will set a diagnostic trouble
code.
5. The “SRS Diagnostic System Check” must be the
starting point of any SRS diagnostics. The “SRS
Diagnostic System Check” will verify proper “AIR
BAG” warning lamp operation and will lead you to
the correct chart to diagnose any SRS
malfunctions. Bypassing these procedures ma
y
result in extended diagnostic time, incorrect
diagnosis, and incorrect parts replacements.

Inspections Required After An Accident
CAUTION: Certain SRS components must be
replaced after a frontal crash involving air bag
deployment.
In all types of accidents regardless of “Air Bag”
deployment, visually inspect all of the following
components and replace as required:

9A-48 SUPPLEMENTAL RESTRAINT SYSTEM

Special Tools
WARNING: TO AVOID DEPLOYMENT WHEN
TROUBLESHOOTING THE SRS, DO NOT USE
ELECTRICAL TEST EQUIPMENT SUCH AS A
BATTERY–POWERED OR AC–POWERED
VOLTMETER, OHMMETER, ETC., OR ANY TYPE
OF ELECTRICAL EQUIPMENT OTHER THAN THAT
SPECIFIED IN THIS MANUAL. DO NOT USE A
NONPOWERED PROBE–TYPE TESTER.
INSTRUCTIONS IN THIS MANUAL MUST BE
FOLLOWED CAREFULLY, OTHERWISE
PERSONAL INJURY MAY RESULT.

5-8840-2421-0 SRS Driver/Passenger Load
Tool
901RS146
The SRS Driver/Passenger Load Tool 5-8840-2421-0
is used only when called for in this section. It is used
as a diagnostic aid and safety device to prevent
inadvertent air bag assembly deployment.
The load tool has three yellow connectors attached to
its case.
The three small connectors are electrically functional
and serve as resistive load substitutions.
No more than two connectors are used at any time.
One of the small connectors is used to substitute for
the load of the driver air bag assembly when it is
connected at the top of the column to the SRS coil
assembly. Another small connector is used to
substitute for the load of the driver air bag assembly
and the SRS coil assembly when it is connected at the
base of the column to the SRS wiring harness. The
third small connector is used to substitute for the load
of the passenger air bag assembly when connected to
the passenger air bag assembly harness connector.
By substituting the resistance of the load tool when
called for, a determination can be made as to whether
an inflator circuit component is causing system
malfunction and which component is causing the
malfunction. The load tool should be used only when
specifically called for in the diagnostic procedures.

5-8840-0285-0 DVM
901RS163
The 5-8840-0285-0 DVM is the preferred DVM for use
in SRS diagnosis and repair. However, 5-8840-0366-
0 may be used if 5-8840-0285-0 is not available. No
other DVMs are approved for SRS diagnosis and
repair.

Scan Tool
901RW176

RESTRAINT CONTROL 9A1-3

Diagnostic Information
CAUTION: When fasteners are removed, always
reinstall them at the same location from which they
were removed. if a fastener needs to be replaced,
use the correct part number fastener for that
application. if the correct part number fastener is
not available, a fastener of equal size and strength
(or stronger) may be used. fasteners that are not
reused, and those requiring thread locking
compound will be called out. the correct torque
value must be used when installing fasteners that
require it. if the above conditions are not followed,
parts or system damage could result.


Diagnostic Procedures
WARNING: TO AVOID DEPLOYMENT WHEN
TROUBLESHOOTING THE SRS, DO NOT USE
ELECTRICAL TEST EQUIPMENT SUCH AS A
BATTERY-POWERED OR AC-POWERED
VOLTMETER, OHMMETER, ETC., OR ANY TYPE OF
ELECTRICAL EQUIPMENT OTHER THAN THAT
SPECIFIED IN THIS MANUAL. DO NOT USE A NON
POWERED, PROBE-TYPE TESTER.
INSTRUCTIONS IN THIS MANUAL MUST BE
FOLLOWED CAREFULLY, OTHERWISE PERSONAL
INJURY MAY RESULT.
The diagnostic procedures used in this section are
designed to aid in finding and repairing SRS problems.
Outlined below are the steps to find and repair SRS
problems quickly and effectively. Failure to carefully
follow these procedures may result in extended
diagnostic time, incorrect diagnosis and incorrect parts
replacement.
1. Perform The “SRS Diagnostic System Check”.
The “SRS Diagnostic System Check” should always
be the starting point of any SRS diagnostics. The
“SRS Diagnostic System Check” checks for prope
r
“AIR BAG” warning lamp operation and checks for
SRS trouble codes using both “Flash Code” and
“Scan Tool” Methods.
2. Refer To The Proper Diagnostic Chart As
Directed By The “SRS Diagnostic System
Check”.
The “SRS Diagnostic System Check” will lead you to
the correct chart to diagnose any SRS problems.
Bypassing these procedures may result in extended
diagnostic time, incorrect diagnosis and incorrect
parts replacement.

3. Repeat The “SRS Diagnostic System Check”
After Any Repair Or Diagnostic Procedures Have
Been Performed.
Preforming the “SRS Diagnostic System Check”
after all repair or diagnostic procedures will assure
that the repair has been made correctly and that no
other conditions exist.

Diagnostic Codes
The SRS control unit maintains a history record of all
diagnostic codes that have been detected since the
SRS codes were last cleared during service.
1. Active Codes - Faults that are presently detected this
ignition cycle. Active codes are stored in RAM
(Random Access Memory).
2. History Codes - All faults detected since the last time
the history fault memory was cleared. History codes
are stored in EEPROM. (Electronically Erasable
Programmable Read only Memory)

How To Read Trouble Codes
All codes (Active and history) can be read (or cleared)
by using a scan tool or equivalent.
If a PDT is not available, have the vehicle serviced by
HOLDEN dealer.

How To Clear Trouble Codes
Trouble codes can only be cleared by using a Scan
Tool. If a “scan tool” is not available then inform the
owner of the stored codes and suggest that the codes
are cleared upon the next visit to an Isuzu dealership.

Scan Tool Diagnostics
A scan tool can be used to read current and history
codes and to clear all history codes after a repair is
complete. The scan tool must be updated to
communicate with the SRS through a replaceable
cartridge or a manufacturer's update before it can be
used for SRS diagnostics. To use the scan tool,
connect it to the DLC connector and turn the ignition
switch “ON”. Then follow the manufacturer's directions
for communication with the SRS. The scan tool reads
serial data from the SRS control unitSRS control unit
“Serial Data” output (terminal 21) to the DLC connector
(terminal 2).

Basic Knowledge Required
Before using this section of the Service Manual, there is
some basic knowledge which will be required. Without
this knowledge, you will have trouble using the
diagnostic procedures in this section. Use care to
prevent harm or unwanted deployment. Read all

RESTRAINT CONTROL 9A1-59

DTC B0670 (Flash Code 63) Airbag Telltale Circuit Malfunction


RTW49JLF000101

Circuit Description
When the ignition switch is turned “ON”, battery voltage
is applied to the “AIR BAG” warning lamp and to the
“Ignition 1” input terminal “35”. The SRS control unit
responds by flashing the “AIR BAG” warning lamp
seven times. The SRS control unit monitors the lamp
driver output by comparing the output state at “SRS
Warning Lamp” terminal “39” to the microprocesso
r
commanded state. When “Ignition 1” is in the specified
value, and the output state does not match the
commanded state of the lamp driver for 500
milliseconds, DTC B0670 is set.


DTC Will Set When
“Ignition 1” voltage is in the specified value and the
output state at the “SRS Warning Lamp” terminal does
not match the commanded state of the lamp driver for
500 milliseconds. This test is run every 100
milliseconds during “Continuous Monitoring” tests and
once per each ignition cycle at the beginning.

Action Taken
SRS control unit attempts to turn “ON” the “AIR BAG”
warning lamp and sets a diagnostic trouble code.

DTC Will Clear When
The ignition switch is turned “OFF.”

BRAKE CONTROL SYSTEM 5A-3

DTC C0235 (Flash Code 35) Rear Left Wheel Speed Sensor Short Circuit or
Circuit Open .................................................................................................................... 5A-62
DTC C0236 (Flash Code 36) Rear Left Wheel Speed Sensor Incorrect Signal ............. 5A-64
DTC C0237 (Flash Code 37) Rear Left Wheel Speed Sensor Signal - Tooth
Chipping ........................................................................................................................... 5A-66
DTC C0238 (Flash Code 38) Tire Diameter Error ............................................................. 5A-68
DTC C0241 (Flash Code 41) Front Right Isolation Solenoid Circuit Open or
Shorted to Ground ........................................................................................................... 5A-69
DTC C0242 (Flash Code 42) Front Right Dump Solenoid Circuit Open or Shorted
to Ground.......................................................................................................................... 5A-69
DTC C0243 (Flash Code 43) Front Right Isolation Solenoid Circuit Shorted to
Battery............................................................................................................................... 5A-69
DTC C0244 (Flash Code 44) Front Right Dump Solenoid Circuit Shorted to
Battery............................................................................................................................... 5A-69
DTC C0245 (Flash Code 45) Front Left Isolation Solenoid Circuit Open or
Shorted to Ground ........................................................................................................... 5A-71
DTC C0246 (Flash Code 46) Front Left Dump Solenoid Circuit Open or Shorted
to Ground.......................................................................................................................... 5A-71
DTC C0247 (Flash Code 47) Front Left Isolation Solenoid Circuit Shorted to
Battery............................................................................................................................... 5A-71
DTC C0248 (Flash Code 48) Front Left Dump Solenoid Circuit Shorted to
Battery............................................................................................................................... 5A-71
DTC C0251 (Flash Code 51) Rear Isolation Solenoid Circuit Open or Shorted to
Ground .............................................................................................................................. 5A-73
DTC C0252 (Flash Code 52) Rear Dump Solenoid Circuit Open or Shorted to
Ground .............................................................................................................................. 5A-73
DTC C0253 (Flash Code 53) Rear Isolation Solenoid Circuit Shorted to Battery ......... 5A-73
DTC C0254 (Flash Code 54) Rear Dump Solenoid Circuit Shorted to Battery .............. 5A-73
DTC C0265 (Flash Code 65) Fail Safe Relay (FSR) Shorted to Ground ......................... 5A-75
DTC C0266 (Flash Code 66) Fail Safe Relay (FSR) Shorted to Battery.......................... 5A-75
DTC C0267 (Flash Code 67) ABS Motor Shorted to Ground .......................................... 5A-77
DTC C0268 (Flash Code 68) ABS Motor Shorted to Battery ........................................... 5A-77
DTC C0271 (Flash Code 71) ECU Failure or Valve +B Circuit Open .............................. 5A-79
DTC C0274 (Flash Code 74) ABS Operation Long Time ................................................. 5A-80
DTC C0276 (Flash Code 76) G-Sensor Malfunction ........................................................ 5A-82

BRAKE CONTROL SYSTEM 5A-17

EHCU Pin-outs


C05L300005

EHCU Side
Pin No.
(Harness
side
Pin No.) Pin Function Wire
Color Typical Value Note
1
(C67-11) Power Supply WHT/GRN Battery Voltage Solenoid
2
(C67-10) Ground 1 BLK 0V
(Less than 0.1V) Solenoid, Control Unit
3
(C67-28) Ground 2 BLK 0V
(Less than 0.1V) Motor
4
(C67-27) Power Supply WHT/RED Battery Voltage Motor
5
(C67-9) Stop Light Switch RED Open : 0V
Close : Battery Voltage Close Condition :
Step on the Brake Pedal
6
(C67-8) Serial ORN/WHT - J1850 Class 2
Communication
7
(C67-7) Serial GRN - J1850 Class 2
Communication
8
(C67-6) Not Used - -
9
(C67-5) Not Used - -
10
(C67-4) G-Sensor Ground BLK 0V
(Less than 0.1V) 4WD Only
DTC C0276, C0285
11
(C67-3) Front Right Wheel Speed Sensor (-) GRY High Level: 1.28~2.2V
Low Level: 0.5~0.86V DTC C0221,C0222,
C0223
12
(C67-2) Front Right Wheel Speed Sensor (+) GRY/RED 12

1.5V DTC C0221,C0222,
C0223
13
(C67-1) Rear Right Wheel Speed Sensor (-) BLK High Level: 1.28~2.28V
Low Level: 0.5~0.86V DTC C0231,C0232,
C0233

5A-18 BRAKE CONTROL SYSTEM

EHCU Side
Pin No.
(Harness
side
Pin No.) Pin Function Wire
Color Typical Value Note
14
(C67-17) ABS Warning Lamp YEL More than 10V
15
(C67-16) Not Used - -
16
(C67-15) Not Used - -
17
(C67-14) G-Sensor Signal YEL/BLK 2.0~3.0V
(MAX4.0V,MIN1.0V) 4WD Only
It checks in a flat place
(0G:2.5V)
DTC C0276, C0285
18
(C67-13) Front Left Wheel Speed Sensor (+) RED 12

1.5V DTC C0225, C0226,
C0227
19
(C67-12) Rear Right Wheel Speed Sensor (+) ORN 12

1.5V DTC C0231,C0232,
C0233
20
(C67-26) EBD (Brake) Warning Lamp LT BLU More than 10V
21
(C67-25) Starter Switch ON
(Power Supply and Switch Position) BLU/WHT Battery Voltage Control Unit
DTC C0277,C0278
22
(C67-22) Not Used - -
23
(C67-23) Not Used - -
24
(C67-22) Not Used - -
25
(C67-21) Transfer (2-4WD Control Unit) GRY Pulse Signal
(High 4.5V, Low 1.5V) 4WD Only
DTC C0282
26
(C67-20) Front Left Wheel Speed Sensor (-) WHT High Level: 1.28~2.2V
Low Level: 0.5~0.86V DTC C0225, C0226,
C0227
27
(C67-19) Rear Left Wheel Speed Sensor (+) GRY/BLU 12

1.5V
DTC C0235, C0236,
C0237
28
(C67-18) Rear Left Wheel Speed Sensor (-) WHT/BLU High Level: 1.28~2.2V
Low Level: 0.5~0.86V DTC C0235, C0236,
C0237

BRAKE CONTROL SYSTEM 5A-21

Computer System Service Precautions
The Anti-lock Brake System and Electronic Brake-force
Distribution interfaces directly with the Electronic
Hydraulic Control Unit (EHCU) which is a control
computer that is similar in some regards to the Engine
Control Module. These modules are designed to
withstand normal current draws associated with vehicle
operation. However, care must be taken to avoid
overloading any of the EHCU circuits. In testing for
opens or shorts, do not ground or apply voltage to any
of the circuits unless instructed to do so by the
appropriate diagnostic procedure. These circuits should
only be tested with a high impedance multimeter
5-8840-0366-0 or special tools as described in this
section. Power should never be removed or applied to
any control module with the ignition in the “ON”
position.
Before removing or connecting battery cables, fuses or
connectors, always turn the ignition switch to the “OFF”
position.

General Service Precautions
The following are general precautions which should be
observed when servicing and diagnosing the Anti-lock
Brake System and/or other vehicle systems. Failure to
observe these precautions may result in Anti-lock Brake
System and Electronic Brake-force Distribution
damage.
 If welding work is to be performed on the vehicle
using an electric arc welder, the EHCU and valve
block connectors should be disconnected before
the welding operation begins.
 The EHCU and valve block connectors should
never be connected or disconnected with the
ignition “ON”.
Note:
 If only rear wheels are rotated using jacks or drum
tester, the system will diagnose a speed sensor
malfunction and the “ABS and Brake” warning lamp
will illuminate. But actually no trouble exists. When
the DTC is not detected and the ABS and BRAKE
warning lamp is on, “How to erase code” is
performed and a ABS and BRAKE warning lamp
are off.
If the battery has been discharged
The engine may stall if the battery has been completely
discharged and the engine is started via jumper cables.
This is because the Anti-lock Brake System (ABS) and
Electronic Brake-force Distribution (EBD) System
requires a large quantity of electricity. In this case, wait
until the battery is recharged, or set the ABS and EBD
to a non-operative state by removing the fuse for the
ABS. After the battery has been recharged, stop the
engine and install the ABS fuse. Start the engine again,
and confirm that the ABS warning Lamp does not light.
Note on Intermittents
As with virtually any electronic system, it is difficult to
identify an intermittent failure. In such a case
duplicating the system malfunction during a test drive or
a good description of vehicle behavior from the
customer may be helpful in locating a “most likely”
failed component or circuit. The symptom diagnosis
chart may also be useful in isolating the failure. Most
intermittent problems are caused by faulty electrical
connections or wiring. When an intermittent failure is
encountered, check suspect circuits for:
 Suspected harness damage.
 Poor mating of connector halves or terminals not
fully seated in the connector body (backed out).
 Improperly formed or damaged terminals.

Test Driving ABS Complaint Vehicles
In case that there has been an abnormality in the
lighting pattern of “ABS” warning lamp, the fault can be
located in accordance with the “DIAGNOSIS BY “ABS”
WARNING LAMP ILLUMINATION PATTERN”. In case
of such trouble as can be detected by the driver as a
vehicle symptom, however, it is necessary to give a test
drive following the test procedure mentioned below,
thereby reproducing the symptom for trouble diagnosis
on a symptom basis:
1.
Start the engine and make sure that the “ABS” W/L
goes OFF. If the W/L remains ON, it means that
the Diagnostic Trouble Code (DTC) is stored.
Therefore, read the code and locate the fault.
Note: The DTC cannot be cleared if the vehicle speed
does not exceed about 6km/h (4mph) at DTC, even
though the repair operation is completed.
2. Start the vehicle and accelerate to about 30 km/h
(19 mph) or more.
3. Slowly brake and stop the vehicle completely.
4. Then restart the vehicle and accelerate to about 40
km/h (25 mph) or more.
5. Brake at a time so as to actuate the ABS and stop
the vehicle.
6. Be cautious of abnormality during the test. If the
W/L is actuated while driving, read the DTC and
locate the fault.
7. If the abnormality is not reproduced by the test,
make best efforts to reproduce the situation
reported by the customer.
8. If the abnormality has been detected, repair in
accordance with the “SYMPTOM DIAGNOSIS” .
Note:

Be sure to give a test drive on a wide, even road
with a small traffic.
 If an abnormality is detected, be sure to suspend
the test and start trouble diagnosis at once.